Ap4StscAtom.cpp

/***************************************************************** | | AP4 - stsc Atoms | | Copyright 2002-2005 Gilles Boccon-Gibod & Julien Boeuf | | | This file is part of Bento4/AP4 (MP4 Atom Processing Library). | | Unless you have obtained Bento4 under a difference license, | this version of Bento4 is Bento4|GPL. | Bento4|GPL is free software; you can redistribute it and/or modify | it under the terms of the GNU General Public License as published by | the Free Software Foundation; either version 2, or (at your option) | any later version. | | Bento4|GPL is distributed in the hope that it will be useful, | but WITHOUT ANY WARRANTY; without even the implied warranty of | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | GNU General Public License for more details. | | You should have received a copy of the GNU General Public License | along with Bento4|GPL; see the file COPYING. If not, write to the | Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA | 02111-1307, USA. | ****************************************************************/ /*---------------------------------------------------------------------- | includes +---------------------------------------------------------------------*/ #include "Ap4.h" #include "Ap4StscAtom.h" #include "Ap4AtomFactory.h" #include "Ap4Utils.h" /*---------------------------------------------------------------------- | AP4_StscAtom::AP4_StscAtom +---------------------------------------------------------------------*/ AP4_StscAtom::AP4_StscAtom() : AP4_Atom(AP4_ATOM_TYPE_STSC, 4+AP4_FULL_ATOM_HEADER_SIZE, true), m_CachedChunkGroup(0) { } /*---------------------------------------------------------------------- | AP4_StscAtom::AP4_StscAtom +---------------------------------------------------------------------*/ AP4_StscAtom::AP4_StscAtom(AP4_Size size, AP4_ByteStream& stream) : AP4_Atom(AP4_ATOM_TYPE_STSC, size, true, stream), m_CachedChunkGroup(0) { AP4_UI32 first_sample = 1; AP4_UI32 entry_count; stream.ReadUI32(entry_count); while (entry_count--) { AP4_UI32 first_chunk; AP4_UI32 samples_per_chunk; AP4_UI32 sample_description_index; if (stream.ReadUI32(first_chunk) == AP4_SUCCESS && stream.ReadUI32(samples_per_chunk) == AP4_SUCCESS && stream.ReadUI32(sample_description_index) == AP4_SUCCESS) { if (m_Entries.ItemCount() != 0) { AP4_Ordinal prev = m_Entries.ItemCount()-1; if (first_chunk == m_Entries[prev].m_FirstChunk) { continue; } m_Entries[prev].m_ChunkCount = first_chunk-m_Entries[prev].m_FirstChunk; first_sample += m_Entries[prev].m_ChunkCount * m_Entries[prev].m_SamplesPerChunk; } m_Entries.Append(AP4_StscTableEntry(first_chunk, first_sample, samples_per_chunk, sample_description_index)); } } } /*---------------------------------------------------------------------- | AP4_StscAtom::WriteFields +---------------------------------------------------------------------*/ AP4_Result AP4_StscAtom::WriteFields(AP4_ByteStream& stream) { AP4_Result result; // entry count AP4_Cardinal entry_count = m_Entries.ItemCount(); result = stream.WriteUI32(entry_count); // entries for (AP4_Ordinal i=0; i<entry_count; i++) { stream.WriteUI32(m_Entries[i].m_FirstChunk); if (AP4_FAILED(result)) return result; stream.WriteUI32(m_Entries[i].m_SamplesPerChunk); if (AP4_FAILED(result)) return result; stream.WriteUI32(m_Entries[i].m_SampleDescriptionIndex); if (AP4_FAILED(result)) return result; } return result; } /*---------------------------------------------------------------------- | AP4_StscAtom::AddEntry +---------------------------------------------------------------------*/ AP4_Result AP4_StscAtom::AddEntry(AP4_Cardinal chunk_count, AP4_Cardinal samples_per_chunk, AP4_Ordinal sample_description_index) { AP4_Ordinal first_chunk; AP4_Ordinal first_sample; AP4_Cardinal entry_count = m_Entries.ItemCount(); if (entry_count == 0) { // first entry first_chunk = 1; first_sample = 1; } else { first_chunk = m_Entries[entry_count-1].m_FirstChunk+ m_Entries[entry_count-1].m_ChunkCount; first_sample = m_Entries[entry_count-1].m_FirstSample+ m_Entries[entry_count-1].m_ChunkCount* m_Entries[entry_count-1].m_SamplesPerChunk; } m_Entries.Append(AP4_StscTableEntry(first_chunk, first_sample, chunk_count, samples_per_chunk, sample_description_index)); // update the atom size m_Size += 12; return AP4_SUCCESS; } /*---------------------------------------------------------------------- | AP4_StscAtom::GetChunkForSample +---------------------------------------------------------------------*/ AP4_Result AP4_StscAtom::GetChunkForSample(AP4_Ordinal sample, AP4_Ordinal& chunk, AP4_Ordinal& skip, AP4_Ordinal& sample_description) { // preconditions AP4_ASSERT(sample > 0); // decide whether to start the search from the cached index // or from the start AP4_Ordinal group; if (m_CachedChunkGroup < m_Entries.ItemCount() && m_Entries[m_CachedChunkGroup].m_FirstSample <= sample) { group = m_CachedChunkGroup; } else { group = 0; } // find which group of chunk contains this one while (group < m_Entries.ItemCount()) { AP4_Cardinal sample_count = m_Entries[group].m_ChunkCount*m_Entries[group].m_SamplesPerChunk; if (sample_count == 0) { // unlimited samples in this group (last group) if (m_Entries[group].m_FirstSample > sample) { // something is wrong return AP4_ERROR_INVALID_FORMAT; } } else { // normal group if (m_Entries[group].m_FirstSample + sample_count <= sample) { // the sample is not in this group group++; continue; } } // the sample is in this group if (m_Entries[group].m_SamplesPerChunk == 0) { // something is wrong return AP4_ERROR_INVALID_FORMAT; } unsigned int chunk_offset = ((sample-m_Entries[group].m_FirstSample) / m_Entries[group].m_SamplesPerChunk); chunk = m_Entries[group].m_FirstChunk + chunk_offset; skip = sample - (m_Entries[group].m_FirstSample + m_Entries[group].m_SamplesPerChunk*chunk_offset); sample_description = m_Entries[group].m_SampleDescriptionIndex; // cache the result (to accelerate finding the right group // next time around m_CachedChunkGroup = group; return AP4_SUCCESS; } // chunk not found chunk = 0; skip = 0; sample_description = 0; return AP4_ERROR_OUT_OF_RANGE; } /*---------------------------------------------------------------------- | AP4_StscAtom::InspectFields +---------------------------------------------------------------------*/ AP4_Result AP4_StscAtom::InspectFields(AP4_AtomInspector& inspector) { inspector.AddField("entry_count", m_Entries.ItemCount()); // dump table entries //for (unsigned int i=0; i<m_Entries.GetItemCount(); i++) { // char dump[256]; // sprintf(dump, " f=%ld, spc=%ld, sdi=%ld\n", // m_Entries[i].m_FirstChunk, // m_Entries[i].m_SamplesPerChunk, // m_Entries[i].m_SampleDescriptionIndex); // stream.WriteString(prefix); // stream.WriteString(dump); //} return AP4_SUCCESS; }

↑ V649 There are two 'if' statements with identical conditional expressions. The first 'if' statement contains function return. This means that the second 'if' statement is senseless. Check lines: 97, 99.